Handling of traffic flows in a communications system

ABSTRACT

The embodiments herein relate to a method in a policy node configured to handle traffic flows in a communications system. The policy node allocates a label-setting identifying a label, a particular traffic flow that will pass through a SDN, and one or more destinations for the particular traffic flow. The policy node transmits information indicating the label-setting to a SDNC configured to create a path for the traffic flow through the SDN based on the label and said one or more destinations identified by the label-setting. The policy node allocates a filter-setting defining that the particular traffic flow should be associated with the label. The policy node transmits information indicating the filter-setting to a classifying node configured to receive the particular traffic flow and to associate the particular traffic flow with the label.

This application is a 35 U.S.C. § 371 national phase filing ofInternational Application No. PCT/EP2014/056426, filed Mar. 31, 2014,the disclosure of which is incorporated herein by reference in itsentirety.

TECHNICAL FIELD

Embodiments herein relate generally to a policy node, a method in thepolicy node, a classifying node, a method in the classifying node, aSoftware Defined Network Controller (SDNC), a method in the SDNC, acomputer program product and a computer program. More particularly theembodiments herein relate to handling traffic flows in a communicationssystem.

BACKGROUND

Software Defined Network/Networking (SDN) involves decoupling networkcontrol from forwarding functions and allowing a centralized networkcontroller to control the behaviour of the entire network. Thus, anetwork operator may, via high level SDN controller, specify thebehaviour of the entire network compared to conventional networks inwhich the network operator needs to perform low level configuration ofeach device in order to specify the behaviour of the network. The staticarchitecture of conventional networks are not known to be optimal fortoday's constantly changing dynamic traffic patterns, increasing storageneeds, increased network complexity etc. One of the purposes of the SDNis to overcome these shortcomings of such conventional networks. Inother words, a SDN enables flexible implementation of networks that maybe dynamically provisioned.

Service chaining is a concept that has obtained increased importancewith the rise of SDN. A service chain may be described as at least oneservice in a specific order and chained together to provide a completeservice. Service chaining may be described as a mechanism for creatingservice chains and forwarding traffic flows through the chains. Theforwarding of the traffic flows may be based on subscription. With SDNs,network operators are enabled to dynamically handle (e.g. create,modify, remove) service chains. A traffic flow may be forwarded througha service path in a service chain, and there may be multiple servicepaths in a service chain. A traffic flow may consist of data packets.

Currently, service chaining is mostly done through selection ofindividual user sessions with five-tuple filtering for every hop in theservice chain. Another solution is that all selected traffic need topass a service, independent of whether it is needed, just to simplifythe traffic steering rules. In other words, without service chaining,all traffic flows need to pass a service for it to affect the trafficthat is actually is interested in.

A problem with existing solutions is that they are scaling poorly foreither the number of different traffic paths that may be handled (due tocomplexity to configure and set up), or the number of users that may besteered into the different traffic paths (due to the number of rulesthat need to be maintained to select them).

Another problem is that the scaling in the downlink direction istroublesome independent of the problems above as it is always scalingpoorly for the number of users/sessions in line with the problemregarding that the number of users that may be steered into thedifferent traffic paths as mentioned above.

Furthermore for Layer 2 (L2)—based service chaining, services, alsoreferred to as applications, are unaware of the topology in the networkand the applications/services will then in most cases destroy thetagging/chain data on L2 and a new classification is needed by thenetwork to restore the tagging/chain data once an application/servicehas been applied to a traffic flow.

When selecting a path through several services for a specific flow, thetotal number of rules that need to be maintained throughout the path isa problem.

SUMMARY

An objective of embodiments herein is therefore to obviate at least oneof the above disadvantages and to provide improved handling of trafficflows in a communications system.

According to a first aspect, the objective is achieved by a method in apolicy node configured to handle traffic flows in a communicationssystem. The policy node allocates a label setting identifying a label, aparticular traffic flow that will pass through a SDN and one or moredestinations for the particular traffic flow. The policy node transmitsinformation indicating the label-setting to a SDNC configured to createa path for the traffic flow through the SDN based on the label and saidone or more destinations identified by the label setting. The policynode allocates a filter setting defining that the particular trafficflow should be associated with the label. The policy node transmitsinformation indicating the filter setting to a classifying nodeconfigured to receive the particular traffic flow and to associate theparticular traffic flow with the label.

According to a second aspect, the objective is achieved by a method in aclassifying node configured to receive and handle traffic flows in acommunications system. The classifying node receives from a policy node,information indicating a filter setting defining that a particulartraffic flow should be associated with a label. The classifying nodeclassifies received traffic flows based on the filter setting such thatthe particular traffic flow is identified. The classifying nodeassociates, based on the classification, the particular traffic flowwith the label such that the particular traffic flow comprises thelabel. The classifying node transmits the particular traffic flowcomprising the label to the SDN switch in a SDN. The SDN switch isconfigured to pass the traffic flow through the SDN based on the label.

According to a third aspect, the objective is achieved by a method in aSDNC configured to handle traffic flow in a communications system. TheSDNC receives information indicating a label setting from a policy node.The label setting identifies a label, a particular traffic flow thatwill pass through a SDN controlled by the SDNC, and one or moredestinations for the particular traffic flow. The SDNC creates, based onsaid one or more destinations, a path setting comprising the label and apath for the particular traffic flow through the SDN. The SDNC transmitsinformation indicating the path setting to one or more SDN switches inthe SDN.

According to a fourth aspect, the objective is achieved by a policy nodeconfigured to handle traffic flows in a communications system. Thepolicy node is further configured to allocate a label settingidentifying a label, a particular traffic flow that will pass through aSDN and one or more destinations for the particular traffic flow. Thepolicy node is configured to transmit information indicating thelabel-setting to a SDNC configured to create a path for the traffic flowthrough the SDN based on the label and said one or more destinationsidentified by the label setting. The policy node is configured toallocate a filter setting defining that the particular traffic flowshould be associated with the label. Furthermore, the policy node isconfigured to transmit information indicating the filter setting to aclassifying node configured to receive the particular traffic flow andto associate the particular traffic flow with the label.

According to a fifth aspect, the objective is achieved by a classifyingnode configured to receive and handle traffic flows in a communicationssystem. The classifying node is further configured to receive from apolicy node, information indicating a filter setting defining that aparticular traffic flow should be associated with a label. Theclassifying node is configured to classify received traffic flows basedon the filter setting such that the particular traffic flow isidentified. The classifying node is further configured to associatebased on the classification, the particular traffic flow with the labelsuch that the particular traffic flow comprises the label. Furthermore,the classifying node is configured to transmit the particular trafficflow comprising the label to a SDN switch in a SDN. The SDN switch isconfigured to pass the traffic flow through the SDN based on the label.

According to a sixth aspect, the objective is achieved by a SDNCconfigured to handle traffic flow in a communications system. The SDNCbeing further configured to receive information indicating alabel-setting from a policy node. The label-setting identifies a label,a particular traffic flow that will pass through a SDN controlled by theSDNC and one or more destinations for the particular traffic flow. TheSDNC is configured to create, based on said one or more destinations, apath-setting comprising the label and a path for the particular trafficflow through the SDN. The SDNC is further configured to transmitinformation indicating the path-setting to one or more SDN switches inthe SDN.

Since the traffic flow is steered through a set of services based on thelabel-setting, the handling of traffic flows in the communication systemis improved. The label may, on the ingress of a chain of destinations beset to indicate the path to traverse, and then all sessions matching thelabel may be steered on that alone, instead of creating rules permatching traffic flow or group of traffic flows.

Embodiments herein afford many advantages, of which a non-exhaustivelist of examples follows:

An advantage of the embodiments herein may be that it is a simplesolution and is valid for both Internet Protocol version 4 (IPv4) andInternet Protocol version 6 (IPv6).

Another advantage of the embodiments herein is that they may be scalablein terms of supporting more rules compared to the number of rulessupported by known techniques using the same type of hardware, such asSDN switches. Furthermore, the embodiments herein may be future proofsince they are based on IPv6, i.e. a solution based on IPv6 is alsoapplicable for IPv4.

Furthermore, another advantage of the embodiments herein may be thatthey are associated with Layer 3 (L3), i.e. the IP, which makes themtransparent to the underlying network topology, e.g. possible alterationof the packets in a traffic flow made in connection with layers belowLayer 3 will typically not affect the embodiments described herein.

Another advantage of the embodiments herein may be that all sessionmatching the label may be steered on the label alone, instead ofcreating rules per matching traffic flow or group of traffic flows.

Furthermore, another advantage of the embodiments herein may be that thelabel may transparently pass through most services, unless the servicesare explicitly instructed and/or configured to modify it.

The embodiments herein are not limited to the features and advantagesmentioned above. A person skilled in the art will recognize additionalfeatures and advantages upon reading the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments herein will now be further described in more detail inthe following detailed description by reference to the appended drawingsillustrating the embodiments and in which:

FIG. 1 is a schematic block diagram illustrating embodiments of acommunication system.

FIG. 2a-2b are signaling diagrams illustrating embodiments of a method.

FIG. 3 is a schematic block diagram illustrating embodiments of atraffic flow.

FIG. 4 is a schematic block diagram illustrating embodiments of an IPv6header.

FIG. 5 is a flow chart illustrating embodiments of a method performed bya policy node.

FIG. 6 is a schematic block diagram illustrating embodiments of a policynode.

FIG. 7 is a flow chart illustrating embodiments of a method performed bya classifying node.

FIG. 8 is a schematic block diagram illustrating embodiments of aclassifying node.

FIG. 9 is a flow chart illustrating embodiments of a method performed bya SDNC.

FIG. 10 is a schematic block diagram illustrating embodiments of a SDNC.

The drawings are not necessarily to scale and the dimensions of certainfeatures may have been exaggerated for the sake of clarity. Emphasis isinstead placed upon illustrating the principle of the embodimentsherein.

DETAILED DESCRIPTION

FIG. 1 depicts a communications system 100 in which embodiments hereinmay be implemented. The communications system 100 may in someembodiments apply to one or more radio access technologies such as forexample Long Term Evolution (LTE), LTE Advanced, future versions of LTE,Wideband Code Division Multiple Access (WCDMA), Global System for MobileCommunications (GSM), or any other Third Generation Partnership Project(3GPP) radio access technology, or other radio access technologies suchas e.g. Wireless Local Area Network (WLAN).

The communications system illustrated in FIG. 1 comprises a classifyingnode 101. The classifying node 101 is a node which is adapted to performclassification. The classifying node 101 may be a gateway node such ase.g. a Packet Data Network Gateway (PGW). The classifying node 101 maycomprise a Deep Packet Inspection (DPI) function. The classifying node101 may be located within e.g. a core network (not shown in FIG. 1) of atelecommunications network, at the periphery of the core network, or ata periphery of a SDN 105 or within the SDN 105. The classifying node 101is configured to receive a particular traffic flow and to associate aparticular traffic flow with a label, which will be described in moredetail below. A traffic flow may comprise one or more data packets suchas e.g. an IPv4 or IPv6 packet.

The communication system 100 further comprises a policy node 103. Thepolicy node 103 may be e.g. a Policy and Charging Rules Function (PCRF)node or similar. The policy node 103 may be connected to the classifyingnode 101. The policy node 103 may be located outside the SDN 105, e.g.within a core network.

A SDNC 108 is also comprised in the system 100. The SDNC 108 may belocated outside or inside the SDN 105, e.g. it may be located within acore network or it may be located inside the SDN 105. The SDNC 108 isadapted to control the SDN 105. The SDNC 108 may comprise informationprovided in e.g. a plurality of tables, T1, T2, T3, which will bedescribed in more detail later. The SDNC 108 is adapted to communicatewith the policy node 103. The SDNC 108 is configured to create a pathfor a traffic flow through the SDN 105 based on a label and one or moredestinations identified by a label-setting. The label and label-settingwill be described in more detail below.

The SDN 105 comprises a plurality of SDN switches 110. In FIG. 1, theSDN 105 is exemplified to comprise three SDN switches 110, i.e. SDNswitch a 110 a, SDN switch b 110 b and SDN switch c 110 c. The SDN 105may comprise any other suitable number of SDN switches 110 than the oneexemplified in FIG. 1. When the reference number 110 is used in thefollowing, it refers to any of the SDN switches in the SDN 105, unlessotherwise is explicitly stated or follows from the context. Each SDNswitch 110 may comprise information in the form of e.g. a table. Forexample, SDN switch a 110 a may comprise table T1, SDN switch b 110 bmay comprise table T2 and SDN switch 110 c c may comprise table T3. Thetables are provided by the SDNC 108 to the SDN switches 110. Thesetables will be described in more detail later. Each SDN switch 110 isadapted to be controlled by the SDNC 108. At least one of the SDNswitches 110 in the SDN 105 is adapted to communicate with theclassifying node 101. In some embodiments, one of the SDN switches 110,e.g. SDN switch a 110 a is collocated with the classifying node 101.Such collocated node is a node having both a switching capability and aclassifying capability. The SDN switch 110 is configured to pass thetraffic flow through the SDN 105 based on a label, which will describedin more detail below.

A SDN switch 110 may be associated with a service 115. A service 115 maye.g. be a service which provides parental control for a traffic flow, itmay be a firewall, it may be a service which is related to charging orauthentication etc. A service 115 is associated with or connected to theSDN 105, but is preferably located outside the SDN 105. For example, SDNswitch a 110 a may be associated with service a 115 a, i.e. it may passthe traffic flow to service a 115 a, and SDN switch c 110 c may beassociated with service b 115 b, i.e. it may pass the traffic flow toservice b 115 b. When the reference number 115 is used in the following,it refers to any of the services, unless otherwise is explicitly statedor follows from the context. A service may be described as anapplication which may comprise a function that provides a service to atraffic flow. A service which a traffic flow passes in a service chainmay be referred to as a Transparent Value-Added Service (TVAS).

At least one of the SDN switches 110 may be associated with anothernetwork, e.g. such as the Internet 120. In FIG. 1, it is exemplifiedthat SDN switch b 110 b is associated with Internet 120, however anyother of the SDN switches 110 may also or instead be associated withanother network such as e.g. the Internet 120 or similar.

The service 115 and the Internet 120 may also be referred to asdestinations. This may also be seen as a destination provides a service.A destination may be a final or intermediate destination for a trafficflow. A service destination 115 may be an intermediate destination, i.e.a service destination may not be a final destination. In the following,the reference numbers 115, 120 will refer to a destination, regardlessof whether the destination is a service 115, Internet 120, intermediatedestination or a final destination. A destination (intermediate orfinal) may be configured to provide a service to be applied to theparticular traffic flow, and the intermediate destination may provideone or more services in a service chain.

The thick black lines in FIG. 1 illustrate at least one incoming trafficflow. As seen in FIG. 1, the traffic flow enters the classifying node101, goes further through the SDN 105 in the most efficient way whichmay involve at least one of SDN switch a 110 a, SDN switch b 110 b, SDNswitch c 110 c, service a 115 a, service b 115, service c 115 a andinternet 120. For example, a particular traffic flow that only has theinternet 120 as end destination may pass SDN switch a 110 a and SDNswitch b 110 b, but not SDN switch c 110 c unless there are congestionsor breakdown of communication between SDN switch a 110 a and SDN switchb110 b. In case of a congestion of breakdown, the traffic flow may forexample pass through SDN switch a 110 a, SDN switch c 110 c and SDNswitch b 110 b on its way to the Internet 120. Thus, a particulartraffic flow may pass some or all SDN switches 110 in the SDN 105 andsome or all services 115 in a service chain associated with and/orreachable via the SDN 105. The most efficient path a particular trafficflow will take is determined by the SDNC 108. The path of the trafficflow will be described in more detail with reference to FIG. 2 below.

It should be noted that the links in the communications system 100illustrated in FIG. 1 may be of any suitable kind comprising either awired or wireless link. The link may use any suitable protocol dependingon type and level of layer (e.g. as indicated by the Open SystemsInterconnection (OSI) model) as understood by the person skilled in theart.

A method for handle traffic flows in a communications system 100according to some embodiments will now be described with reference tothe signalling diagrams depicted in FIGS. 2a and FIG. 2b . FIG. 2aillustrates steps 201-208. FIG. 2b is a continuation of FIG. 2b andillustrates steps 209-213. In addition to the units seen in FIG. 1, FIG.2b also illustrates a wireless device 125 which may be comprised in thecommunications system 100. The wireless device 125 may be a device bywhich a subscriber may access services offered by an operator's networkand services outside operator's network to which the operators radioaccess network and core network provide access, e.g. access to theInternet. The wireless device 125 may be any device, mobile orstationary, enabled to communicate in the communications network, forinstance but not limited to e.g. user equipment, mobile phone, smartphone, sensors, meters, vehicles, household appliances, medicalappliances, media players, cameras, Machine to Machine (M2M) device,Device to Device (D2D) device, Internet of Things (IoT) device or anytype of consumer electronic, for instance but not limited to television,radio, lighting arrangements, tablet computer, laptop or PersonalComputer (PC). The wireless device 125 may be portable, pocket storable,hand held, computer comprised, or vehicle mounted devices, enabled tocommunicate voice and/or data, via the radio access network, withanother entity, such as another device or a server.

The method illustrated in FIGS. 2a and 2b comprise the following steps,which steps may as well be carried out in another suitable order thandescribed below:

Step 201

This step is illustrated in FIG. 2a . The policy node 103 allocates alabel-setting. The label-setting identifies a label, a particulartraffic flow that will pass through the SDN 105, and one or moredestinations 115 for the particular traffic flow. Thus, thelabel-setting associates a particular traffic flow with a label and oneor more destinations 115, 120 for the particular traffic flow. There maybe may be several labels. In some embodiments one traffic flow may beassociated with one label only. However, in other embodiments it ispreferred that a label is associated with one or more traffic flows,e.g. when different traffic flows are supposed to pass the same servicesor similar. However, it is typically not preferred that one traffic flowis associated with several labels, even though that may be the case insome particular embodiments. The label may e.g. be unique for theparticular traffic flow. A label may be selected based on a selectedservice chain. Alternatively, the label may e.g. be unique for aparticular destination 115 or combination of destinations 115, 120 thata traffic flow will pass. Several different traffic flows that will passthe same destination 115, 120 or the same combination of destinations115, 120 may be associated with the same label. A destination 115, 120may be a final destination and/or an intermediate destination. In someembodiments, the destinations 115, 120 may be described as services 115,and these services 115 may be in a service chain. In other embodiments,the destinations 115, 120 may be Internet 120. In some embodiments, thelabel-setting further identifies the source of the particular trafficflow. The source may e.g. be any type of communication device configuredto communicate with the SDN 105 via the classifying node 101, e.g. suchas the wireless device 125 shown in FIG. 2 b.

Step 202

This step is illustrated in FIG. 2a . When the label-setting has beenallocated in step 201, the policy node 103 sends information indicatingthe label-setting to the SDNC 108. As mentioned above, the SDNC 108 isconfigured to create a path for the particular traffic flow through theSDN 105 based on the label and said one or more destinations 115, 120identified by the label-setting, and possibly also based on the sourceof the particular traffic flow.

Step 203

This step is illustrated in FIG. 2a . When the SDNC 108 has receivedinformation indicating the label-setting, the SDNC 108 creates, based onthe label-setting identifying the label and one or more destinations115, 120 and possibly also the source of the particular traffic flow, apath-setting comprising the label and a path for the particular trafficflow through the SDN 105. The path-setting comprises this information orsimilar organized in for example a table, a tree structure or any othersuitable searchable structure capable of comprising information. Thisstep 203 may therefore involve creating one or more tables T1, T2 and T3or similar as illustrated in FIG. 1. The table, tree or any othersuitable searchable structure comprises the information needed for theSDN switch 110, and this path-setting is created by the SDNC 108, i.e.it is created by a central point in the communications system 100.

The SDN 108 creates the tables or similar for the SDN switches from acentral point in the network based on a common understanding between thepolicy node 103, the classifying node 101, and the SDNC 108 of theassociation of labels and traffic flows, i.e. the policy node 103, theclassifying node 101, and the SDNC 108 associates a particular trafficflow with the same particular label. The tables or similar may be thesame for all SDN switches in the SDN 105, although some switches mayhave one or more individual tables or similar. This is radicallydifferent from prior art SDNs wherein a set of SDN routers or SDNswitches each has a local table and/or local rules or similar beingcreated based on information from the relevant routing protocols and/orsurrounding links and/or surrounding routers/switches etc. Suchrouters/switches will typically comprise different tables depending onthe environment surrounding the particular router/switch. As a contrast,the SDN switches according to embodiments of the present disclosure mayhave the same tables or similar where the tables or similar are createdmore or less independent of the local environment surrounding a singleSDN switch.

An example of table T1 is seen below in table 1. The left columncomprises labels and the right column comprises the path associated withthe respective label.

TABLE 1 Example of table T1 Label Path Label 1 Path 1 (e.g. a, c, b)Label 2 Path 2 (e.g. a, service a, b) Label 3 Path 3 (e.g. a, c, serviceb, b) Label 4 Path 4 (e.g. a, service a, c, service b, b)

As mentioned above, a service 115 and the Internet 120 may be referredto as destinations, and a destination may be a final or intermediatedestination for a traffic flow. In the first row in table 1 above and asseen in FIG. 1 label 1 is exemplified to be associated with path 1. Path1 comprises a, c and b, implying that a traffic flow comprising label 1that is associated with path 1 is supposed to flow through the SDN 105via SDN switches a, c and b (i.e. 110 a, 110 c, 100 b respectively) inthat order. Similarly, label 2 is exemplified to be associated with path2 comprising a, service a and a and b, implying that a traffic flowcomprising label 2 that is associated with path 2 is supposed to flowthrough the SDN 105 via the SDN switch a 110 a, service a 115 a, back tothe SDN switch a 110 a and then to SDN switch b 110 b in that order.

Note that service a 115 a may not have access to any labels or paths orsimilar and it may therefore not be able to perform the forwardingscheme indicated above using labels and paths. However, a service suchas service a 115 a (and also service b 115 b in FIG. 1) may beconfigured to simply return the traffic flow to the nearest sender (i.e.SDN switch a 110 a in case of service a 115 a, and SDN switch c 110 c incase of service b 115 b, see FIG. 1), e.g. based on the identity oraddress (e.g. IP address) of the sender. Such identity or address maye.g. be provided by the sender.

When a traffic flow comprising e.g. label 2 returns from service a 115 ato SDN switch a 110 a, then the SDN switch a 110 a may review the pathand conclude that the traffic flow returning from service a 115 a hasalready been in service a 115 a and shall therefore be forwarded fromservice a 115 a to somewhere else than service a 115 a, and the table inthis case tells the SDN switch a 110 a to forward the traffic flow toSDN switch b 110 b, since b is the next instance that follows afterservice a 115 a in the path. The SDN switch a 110 a may determine thatthe traffic flow returns from service a 115 a e.g. based on the identityor address (e.g. IP address) of the service a 115 a. Such identity oraddress may e.g. be provided by the service a 115 a. Alternatively, theSDN switch a 110 a may mark the traffic flow when it sends it to servicea 115 a, and then check the marking when the traffic flow returns fromservice a 115 a, e.g. leave a mark in the label or similar comprised bythe traffic flow. Those skilled in the art having the benefit of thisdisclosure realises that there are many other ways for SDN switch a 110a to discover that the traffic flow is returned from a service a 115 ato which the SDN switch 110 previously sent the flow in questions.

If the label is at least part of an IP header in Layer 3, the SDNC 108may perform its own method steps compared to if the label should be onan Ethernet Layer 2 level.

Step 204

This step is illustrated in FIG. 2a . The SDNC 108 transmits informationindicating the created path-setting to the SDN switch 110. In case theSDN 105 comprises a plurality of SDN switches 110, the SDNC 108transmits information indicating the path-setting to each SDN switch110. As mentioned above, the information indicating the path-setting maybe in the form of a table, a tree structure or any other suitablesearchable structure comprising the information. For example, in thecase of a table, the SDNC 108 may transmit table T1 to SDN switch a 110a, and table T2 to SDN switch b 110 b and table T3 to SDN switch c 110c. An example of such table is seen in Table 1 above. The tables T1, T2and T3 may comprise the same information, i.e. the SDNC 108 transmitsthe same table to each SDN switch 110. Alternatively, at least one tablemay comprise information uniquely specified for a specific SDN switch110, i.e. the SDNC 108 may transmit different tables to some of the SDNswitches 110.

When a SDN switch 110 receives a traffic flow comprising a label itlooks in the received table (or similar), finds the label and the pathassociated with the label, where the path tells the SDN switch 110 whereto forward the traffic flow. For example (compare FIG. 1), after a SDNswitch c 110 c has received a traffic flow comprising label 1, the SDNswitch c 110 c looks in its path table (e.g. T1), finds label 1 that isassociated with a certain path, e.g. comprising a, c, b. Then, sinceinstance c corresponds to SDN switch c 110 c itself and since instance bcorresponding to SDN switch b is next in the path it enables SDN switchc 110 c to conclude that it shall forward the traffic flow to instanceb. SDN switch b 110 b may e.g. comprise a path table T2. Table T2 may bethe same as T1, but it may be a different table, e.g. wherein label 1 isassociated with a different path e.g. comprising instances a, b,internet. Thus, if SDN switch c 110 c forwards a traffic flow comprisinglabel 10 1 to SDN switch b 110 c (as exemplified above) then SDN switchb 110 b looks in table T2, finds label 1 associated with a pathcomprising instances a, b, Internet 120. Since instance b in this pathcorresponds to the destination of the SDN switch b 110 b itself andsince destination “internet” is next in the path it enables SDN switch b110 b to conclude that it shall forward the traffic flow to the Internet120. This is only one example of how a suitable table or similar may bedefined. However, any other suitable way is possible for defining tablesor similar information structures to be stored in the SDN switches 110and that enables the SDN switches 110 to associate a label with a pathfor a particular traffic flow to follow through the SDN 105, when theparticular traffic flow comprises the label in question.

Step 205

This step is illustrated in FIG. 2a . The SDN switch 110 may store theinformation indicating the path-setting received from the SDNC 108. Incase the information indicating the path-setting is in the form of atable, the SDN switch 110 may store the received table. Thus, each SDNswitch 110 comprises information indicating the path-setting.

Step 206

This step is illustrated in FIG. 2a . The policy node 103 allocates afilter-setting. The filter-setting defines that a particular trafficflow should be associated with a particular label. In the filter-settingeach label is preferably associated with a traffic flow in the same orsimilar manner as each label is associated with a traffic flow by thelabel-setting allocated in step 201. A filter-setting may be used to setlabels in packets, and labels may be used to forward traffic.

The information in the filter-setting indicating the traffic flow(s) ispreferably allocated such that the information enables the classifyingnode 101 to identify the traffic flow(s) in step 210, 703. Theinformation may e.g. indicate the source address of each traffic flow(e.g. source IP address), the source network ID, the source applicationID, source port, or destination address of the traffic flow (e.g.destination IP address), destination port, or any other source ordestination information or any other information that can be used toidentify a traffic flow.

Table 2 below illustrates an example of the association between thelabel and the particular traffic flow in the filter-setting. The leftcolumn comprises information indicating the traffic flow and the rightcolumn comprises information indicating the label for the respectivetraffic flow. As can be seen in table 2, Traffic flow 1 corresponds toLabel 1, Traffic flow 2 corresponds to Label 2,Traffic flow 3corresponds to Label 3, and Traffic flow 4 corresponds to Label 4.

TABLE 2 Filter-setting Traffic flow Label Traffic flow 1 Label 1 Trafficflow 2 Label 2 Traffic flow 3 Label 3 Traffic flow 4 Label 4

Step 207

This step is illustrated in FIG. 2a . The policy node 103 sendsinformation indicating the filter-setting to the classifying node 101.The classifying node 101 is, as mentioned above, configured to receivethe particular traffic flow(s) and to associate the particular trafficflow(s) with a particular label.

The classifying node 101 needs to know which traffic flow to associatewith which label. Once a traffic flow comprises a label and is sent to aSDN switch 110, then the SDN switch 110 comprises its table (e.g. T1) orsimilar information that enables the SDN switch 110 to look up the labelin question and find the associated path that defines how this trafficflow shall flow through the SDN 105.

So, the classifying node 101 knows which traffic flow to mark with whichlabel. The classifying node 101 does not necessarily need to knowanything about paths through the SDN 105. The SDN switches 110 know fromtheir tables or similar which path to use for a particular labelcomprised by a particular traffic flow. The SDN switches 110 do not needto know how the various traffic flows should be associated with thevarious labels to create a filter-setting to be used by the classifyingnode 101.

Step 208

This step is illustrated in FIG. 2a . The classifying node 101 may storethe received information indicating the filter-setting.

Step 209

This step is illustrated in FIG. 2b . The classifying node 101 receivesone or more traffic flows sent by one or more sources, e.g. a wirelessdevice 125. The traffic flow(s) may pass other nodes before it reachesthe classifying node 101.

Step 210

This step is illustrated in FIG. 2b . The classifying node 101classifies the traffic flows received in step 209, preferably based onthe filter-setting received in step 208. The result of the classifyingis that one or more traffic flows are identified.

For example, a particular traffic flow may be identified based on thesource address of the traffic flow (e.g. source IP address), the sourcenetwork ID, the source application ID, source port, destination addressof the traffic flow (e.g. destination IP address), destination port, orany other source or destination determining information or any otherinformation that can be used to identify a traffic flow. Suchinformation enabling an identification of a particular traffic flow maye.g. be comprised or indicated by the information identifying thetraffic flow(s) in the filter-setting.

Step 211

This step is illustrated in FIG. 2b . Based on theclassification/identification of traffic flows in step 210, theclassifying node 101 associates each traffic flow with a label accordingto the filter-setting such that each particular traffic flow comprisesthe corresponding label.

For example, assume that traffic flow 1 defined by the filter-setting intable 2 is received by the classifying node 101 in step 209, and thatthe received traffic flow is identified by the classifying node 101 instep 210. Then the classifying node 101 will associate the identifiedtraffic flow 1 with label 1 such that traffic flow 1 comprises label 1.The label may e.g. be inserted by the classifying node 101 into a headerof one or more data packets comprised by traffic flow 1, e.g. asdescribed above with reference to FIG. 4 showing a schematicillustration of an IPv6 header.

Step 212

This step is illustrated in FIG. 2b . The classifying node 101 transmitsthe identified traffic flows, each comprising the corresponding label,to a SDN switch 110 in the SDN 105. As mentioned earlier, the SDN switch110 is configured to pass the traffic flow through the SDN 105 based onthe label comprised by the traffic flow received from the classifyingnode 101.

Step 213

This step is illustrated in FIG. 2b . When the SDN switch 110 hasreceived the particular traffic flow comprising the label, the SDNswitch 110 may determine a path for the particular traffic flow based onthe label, as exemplified in Table 3 below. The SDN switch 110 may checkwhich label the particular traffic flow comprises and then select a pathbased on the label in the path-setting comprised by the SDN switch 110.In this example the SDN switch 110 may select a path by locating thelabel and the associated path in the table previously created in step203, transmitted to the SDN switch 110 in step 204 and stored in the SDNswitch 110 in step 205. So, a particular traffic flow may reach a numberof destinations 115, 120 on its way through the SDN 105. Suchdestination 115, 120 may be at least one of an intermediate destination115 (also referred to as services) and a final destination such as e.g.Internet 120.

Table 3 below illustrates an example of the association between thetraffic flow, label, path and destinations 115, 120. The left mostcolumn comprises the traffic flow, the left middle column comprises thelabel which is comprised in the respective traffic flow, the rightmiddle column comprises the path with which the label is associated andthe right most column comprises examples of the destinations of thedifferent paths.

TABLE 3 Label Path with comprised which by the the label is Instancesand destinations Traffic flow traffic flow associated of the differentpaths Traffic flow 1 Label 1 Path 1 a, c, b Traffic flow 2 Label 2 Path2 a, service a, b Traffic flow 3 Label 3 Path 3 a c, service b, bTraffic flow 4 Label 4 Path 4 a, service a, c, service b, c, b

The entities in the communications system 100 which the particulartraffic flow may pass through is exemplified in FIG. 3. As seen in FIG.3, the traffic flow enters the classifying node 101 which performs theclassification as described in steps 210 and 211 in FIG. 2b . Then thetraffic flow enters the SDN switch 110 (steps 212 and 213 in FIG. 2b ),which determines the path for the particular traffic flow based on thepath-setting comprised by the SDN switch and the label comprised by thetraffic flow.

One SDN switch 110 may only be able to forward a traffic flow to thenext instance or destination (e.g. another SDN switch 110, a service 115or Internet 120). Then, that instance or destination has to forward thetraffic flow to the next instance or destination and so on. So, atraffic flow which is received by the SDN switch a 110 a from theclassifying node 101, may be forwarded by the SDN switch a 110 a to theservice a 115 a or the SDN switch b 110 b or the SDN switch c 110 c, seeFIG. 1. The actual forwarding operatively performed by the individualSDN switch 110 may be done based on the path setting (see steps204-205), which may for example be represented by tables, informationorganized in a tree structure or any other suitable searchable structurecomprising information. There may be no link or connection betweenservice a 115 a and service b 115 b in FIG. 1, and a traffic flow thatshould pass both service a 115 a and service b 115 b may have to do thatby at last passing via the SDN switches a and c 110 a and 110 c(possibly via all SDN switches a, b, c (i.e. 110 a, 110 b, 110 crespectively), if the connection between the SDN switch a 110 a and theSDN switch c 110 c is down).

The services a 115 a, b 115 b may have no tables or similar searchableinformation-structures After the particular service has been provided tothe traffic flow, the traffic flow may for example be returned to thesending address, i.e. in FIG. 1 returned to the SDN switch a 110 a orthe SDN switch c 110 c that originally forwarded the traffic flow to theparticular services a 115 a, b 115 b respectively.

Label

The label mentioned e.g. in step 201 of FIG. 2a will now be described inmore detail. The label may be a part of a data packet header of one ormore or even all data packets in a particular traffic flow, for exampleat least a part of an IPv6 or IPv4 header. The label may be at leastpart of an extension header or a routing header. The label may forexample be a flow label or a part of a flow label comprised by theheader. In embodiments herein, the flow label is used to determine howto transport the traffic flows in addition to selecting whichdestinations 115, 120 (that may not be involved in payloadtransportation or routing) the traffic flows shall pass.

Including the label in the header of a data packet has the advantagethat it will not be changed by procedures occurring on lower layers.Embodiments herein include the label in the header of the data packet(s)and are therefore affecting Layer 3 (L3) procedures, i.e. the IP. Thismakes the embodiments transparent to the underlying network topology,e.g. possible alteration of the packets in a traffic flow, e.g. made byservices 115 a, 115 b or similar, in connection with layers below Layer3 will typically not affect the embodiments described herein.

An example of an IPv6 header is schematically illustrated in FIG. 4. TheIPv6 header comprises version (4 bits), traffic class (8 bits), flowlabel (bits), payload length (16 bits), next header (8 bits), hop limit(8 bits), source address (128 bits) and destination address (128 bits).The label of embodiments described herein may be comprised by the IPv6flow label or at least be a part of the IPv6 flow label.

Label for Service Chaining or Similar

By using the label, the policy node 103 may set a path identifierindicated by the label for many different traffic flows. This may groupseveral traffic flows into one single path which drastically minimizesthe number of rules that has to be distributed in the network, i.e. theSDN 105. Thus, the label may be used as a tag for both selectingprocessing and functional services.

Labels for Service Identification or Similar

The labels used by embodiments described herein may also be used toidentify what services/policies to use within a certain application. Forexample, a label comprised by a particular traffic flow may correspondto a particular path as described above, and also indicate that aparticular processing/service or similar should be applied to thetraffic flow by a particular service 115 a or 115 b included in thepath. Here, the service 115 a, 115 b may provide several differentprocesses/services that it may apply to the traffic flow based on theinformation comprised by the label. This may be seen as a specializationof a service chain, where different chains are implemented within thesame application and processing element, hence it may also be used toinstantiate the processing within an application.

An example of such a combination may be that a certain label specifiesthat a traffic flow shall be bit-rate limited to A kbps and re-markedwith a DiffServ Code Point (DSCP) with the value C, while another labelwould specify that the traffic flow shall be bit-rate limited to B kbpsand marked with a DiffServ Code Point with the value D.

Traffic Flow Reflection

As traffic flows in most cases would be originating from the wirelessdevice 125 side. However, embodiments herein is equally applicable whenthe traffic flow originates from the opposite side, e.g. from theinternet 120. This implies that the classifying node 101 is arrangedsuch that the traffic flows are received by the classifying node 101,processed as described above, and then sent to SDN switch 110 b.

Moreover, the traffic flows may enter the SDN 105 without first passingthe classifying node 101 as described above, e.g. if only oneclassifying node 101 is used and some traffic flows enters the SDN fromthe end where there is no classifying node. In this connection it may benoted that, many protocols run on top of the Transmission ControlProtocol (TCP) or another protocol that comprises hand-shakes beforehandling the actual payload in the traffic flow. Here, the SDN switch110 located closest to the internet connection 120 may be seen as aclassifier that only has to reflect the classification decisions done inthe other direction. Therefor the traffic flow in that (down-link)direction may be derived from the labels in the other direction(up-link). This may require that the traffic flow is using the same SDNnode 110 in both directions, or that the results are spread over allpotential traffic processing entities.

Traffic Flow Direction

To simplify forwarding even further, the direction of the traffic flowmay be encoded into the label. In an embodiment where the label is theflow label in IPv6, one bit out of the twenty bits in the flow label mayindicate the direction. This enables for easy handling of bi-directionaltraffic flows, especially together with the traffic flow reflectionabove.

IPv4

The IPv4 header does not comprise the flow label as the IPv6 header. Ina case where the label is comprised in an IPv4 header, the IPv4 headermay therefore be translated into an IPv6 header such that a flow labelmay be used. The translation from IPv4 to IPv6 may be performed by thewireless device 125, by the PGW or by any other node within the SDN 105domain.

The method described above will now be described seen from theperspective of the policy node 103. FIG. 5 is a flowchart describing thepresent method in the policy node 103, configured to handle trafficflows in the communications system 100. The policy node 103 may be aPCRF node. The method comprises the following steps to be performed bythe policy node 103, which steps may be performed in any suitable orderdifferent from the one described below:

Step 501

This step corresponds to step 201 in FIG. 2. The policy node 103allocates a label-setting identifying a label, a particular traffic flowthat will pass through a SDN 105, and one or more destinations 115, 120for the particular traffic flow. Thus, the label-setting associates aparticular traffic flow with a label and one or more destinations 115,120 for the particular traffic flow.

The label-setting may further indicate a source for the particulartraffic flow.

At least one of the destinations 115, 120 may be an intermediatedestination 115 configured to provide a service to be applied to theparticular traffic flow. The intermediate destination 115 may provide aservice in a service chain.

The label may be a part of a data packet header of data packets in theparticular traffic flow.

The label may be one of at least a part of a flow label in an IPv6header in data packets of the particular traffic flow and at least apart of a label in an extension header in data packets of the particulartraffic flow.

Step 502

This step corresponds to step 202 in FIG. 2. The policy node 103transmits information indicating the label-setting to the SDNC 108configured to create a path for the traffic flow through the SDN 105based on the label and said one or more destinations 115, 120 identifiedby the label-setting.

Step 503

This step corresponds to step 206 in FIG. 2. The policy node 103allocates a filter-setting defining that the particular traffic flowshould be associated with the label. In the filter-setting each label ispreferably associated with or corresponding to a traffic flow in thesame or similar manner as each label is associated with a traffic flowby the label-setting allocated in step 501 and 201 described above.

The information in the filter-setting indicating the traffic flow(s) ispreferably allocated such that the information enables the classifyingnode 101 to identify the traffic flow(s) in step 210, 703. Theinformation may e.g. indicate the source address of each traffic flow(e.g. source IP address), the source network ID, the source applicationID, source port, or destination address of the traffic flow (e.g.destination IP address), destination port, or any other source ordestination information or any other information that can be used toidentify a traffic flow.

In some embodiments, the filter-setting further indicates a direction ofthe traffic flow. The direction may be uplink from a wireless device 125to a base station or downlink from the base station to the wirelessdevice 125.

The filter-setting may further indicate which services or similar to beused at a destination 115, 120 for the particular traffic flow.

The filter-setting for the traffic flow in one direction may bederivable from a label in another direction.

Step 504

This step corresponds to step 207 in FIG. 2. The policy node 103transmits information indicating the filter-setting to a classifyingnode 101 configured to receive the particular traffic flow and toassociate the particular traffic flow with the label. The classifyingnode 101 may be a gateway node.

In some embodiments, a computer program may comprise instructions which,when executed on at least one processor, cause the at least oneprocessor to carry out the method steps 501-504. A carrier may comprisethe computer program, and the carrier is one of an electronic signal,optical signal, radio signal or computer readable storage medium.

To perform the method steps shown in FIG. 5 for handling traffic flowsin the communications system 100, the policy node 103 is configured tohandle traffic flows in a communications system 100. The policy node 103being further configured to allocate a label-setting identifying alabel, a particular traffic flow that will pass through a SDN 105 andone or more destinations 115, 120 for the particular traffic flow. Thepolicy node is configured to transmit information indicating thelabel-setting to the SDNC 108 configured to create a path for thetraffic flow through the SDN 105 based on the label and said one or moredestinations 115, 120 identified by the label-setting. The policy nodeis configured to allocate a filter-setting defining that the particulartraffic flow should be associated with the label. The policy node isfurther configured to transmit information indicating the filter-settingto a classifying node 101 configured to receive the particular trafficflow and to associate the particular traffic flow with the label.

In some embodiments, the policy node 103 comprises means adapted toallocate a label-setting identifying a label, a particular traffic flowthat will pass through a SDN 105 and one or more destinations 115, 120for the particular traffic flow. The means is adapted to transmitinformation indicating the label-setting to the SDNC 108 configured tocreate a path for the traffic flow through the SDN 105 based on thelabel and said one or more destinations 115, 120 identified by thelabel-setting. The means is adapted to allocate a filter-settingdefining that the particular traffic flow should be associated with thelabel. The means is further adapted to transmit information indicatingthe filter-setting to a classifying node 101 configured to receive theparticular traffic flow and to associate the particular traffic flowwith the label.

To perform the method steps shown in FIG. 5 for handling traffic flowsin the communications system 100 the policy node 103 may comprise anarrangement as shown in FIG. 6. As mentioned above, the policy node 103is configured to handle traffic flows in the communications system 100.The policy node 103 may be a PCRF node.

The policy node 103 may comprise an allocating unit 601 adapted toallocate a label-setting identifying a label, a particular traffic flowthat will pass through the SDN 105, and one or more destinations 115,120 for the particular traffic flow. The label-setting may furtherindicate a source for the particular traffic flow. At least one of thedestinations 115, 120 may be an intermediate destination 115 configuredto provide a service to be applied to the particular traffic flow. Theintermediate destination 115 may provide a service in a service chain.The label may be a part of a data packet header of data packets in theparticular traffic flow. The label may be one of at least a part of aflow label in an IPv6 header in data packets of the particular trafficflow and at least a part of a label in an extension header in datapackets of the particular traffic flow. The allocating unit 601 may befurther adapted to allocate a filter-setting defining that theparticular traffic flow should be associated with the label. Thefilter-setting may further indicate a direction of the traffic flow. Thedirection may be uplink from a wireless device 125 to a base station ordownlink from the base station to the wireless device 125. Thefilter-setting further may indicate which services to be used at adestination 115, 120 for the particular traffic flow. The filter-settingfor the traffic flow in one direction may be derivable from a label inanother direction. The allocating unit 601 may also be referred to as anallocating module, an allocating means, an allocating circuit or meansfor allocating.

The policy node 103 may comprise a transmitting unit 603 which isadapted to transmit information indicating the label-setting to a SDNC108 configured to create a path for the traffic flow through the SDN 105based on the label and said one or more destinations 115, 120 identifiedby the label-setting. The transmitting unit 603 may be further adaptedto transmit information indicating the filter-setting to a classifyingnode 101 configured to receive the particular traffic flow and toassociate the particular traffic flow with the label. The classifyingnode 101 may be a gateway node. The transmitting unit 603 may also bereferred to as a transmitting module, a transmitting means, atransmitting circuit, means for transmitting or an output unit. Thetransmitting unit 603 may be a transmitter, a transceiver etc. Thetransmitting unit 603 may be a wireless transmitter of the policy node103 of a wireless or fixed communications system.

The policy node 103 may comprise a receiving unit 605 which is adaptedto receive information, messages and signaling from other nodes in thecommunications system 100. The receiving unit 605 may also be referredto as a receiving module, a receiving means, a receiving circuit, meansfor receiving or an input unit. The receiving unit 605 may be areceiver, a transceiver etc. The receiving unit 605 may be a wirelessreceiver of the policy node 103 of a wireless or fixed communicationssystem.

In some embodiments, the policy node 103 comprises a processor 608 and amemory 610. The memory 610 comprises instructions executable by theprocessor 608.

The memory 610 may comprise one or more memory units. The memory 610 isarranged to be used to store data, received data, power levelmeasurements, label-settings, filter-settings, information, thresholdvalues, time periods, configurations, schedulings, and applications toperform the methods herein when being executed in the policy node 103.

Those skilled in the art will also appreciate that the allocating unit601, the transmitting unit 603 and the receiving unit 605 describedabove may refer to a combination of analog and digital circuits, and/orone or more processors configured with software and/or firmware, e.g.stored in a memory, that when executed by the one or more processorssuch as the processor 608 perform as described above. One or more ofthese processors, as well as the other digital hardware, may becomprised in a single Application-Specific Integrated Circuit (ASIC), orseveral processors and various digital hardware may be distributed amongseveral separate components, whether individually packaged or assembledinto a System-on-a-Chip (SoC).

The method described above will now be described seen from theperspective of the classifying node 101. FIG. 7 is a flowchartdescribing the present method in the classifying node 101 configured toreceive and handle traffic flows in the communications system 100. Theclassifying node 101 may comprise a Deep Packet Inspection (DPI)function. The classifying node 101 may be a gateway node. The methodcomprises the following steps to be performed by the classifying node101, which steps may be performed in any suitable order different fromthe one described below:

Step 701

This step corresponds to step 207 in FIG. 2. The classifying node 101receives, from the policy node 103, information indicating afilter-setting defining that a particular traffic flow should beassociated with a label.

The information in the filter-setting indicating the traffic flow(s) ispreferably allocated such that the information enables the classifyingnode 101 to identify the traffic flow(s) in step 210, 703.

The label may further indicate a direction of the traffic flow. Thedirection may be uplink from the wireless device 125 to the SDN 105 ordownlink from the SDN 105 to the wireless device 125.

The filter-setting may further indicate which services to be used at adestination 115, 120 for the particular traffic flow.

The filter-setting for the traffic in one direction may be derivablefrom a label in another direction.

The particular traffic flow may be received from a wireless device 125.

The particular traffic flow may be received from the internet 120 orsimilar.

Step 702

This step corresponds to step 210 in FIG. 2. The classifying node 101classifies the traffic flows received in step 209, preferably based onthe filter-setting received in step 701. The result of the classifyingis that one or more traffic flows are identified. In other words, theclassifying node 101 classifies received traffic flows based on thefilter-setting such that particular traffic flows are identified.

This step corresponds to step 211 in FIG. 2. Based on theclassification/identification of traffic flows in step 702, theclassifying node 101 associates each identified traffic flow with alabel according to the filter-setting such that each particular trafficflow comprises the corresponding/associated label. The label may e.g. beinserted by the classifying node 101 into a header of one or more datapackets comprised by traffic flow in question, e.g. as described abovewith reference to FIG. 4 showing a schematic illustration of an IPv6header.

Step 704

This step corresponds to step 212 in FIG. 2. The classifying node 101transmits the particular traffic flow comprising the label to a SDNswitch 110 in the SDN 105. The SDN switch 110 is configured to pass thetraffic flow through the SDN 105 based on the label comprised by thetraffic flow.

In some embodiments, a computer program may comprise instructions which,when executed on at least one processor, cause the at least oneprocessor to carry out the method steps 701-704. A carrier may comprisethe computer program, and the carrier is one of an electronic signal,optical signal, radio signal or computer readable storage medium.

To perform the method steps shown in FIG. 7 for receiving and handlingtraffic flows in the communications system 100, the classifying node 101is configured to receive from a policy node 103, information indicatinga filter-setting defining that a particular traffic flow should beassociated with a label. The classifying node 101 is further configuredto classify received traffic flows based on the filter-setting such thatthe particular traffic flow is identified. The classifying node 101 isconfigured to associate based on the classification, the particulartraffic flow with the label such that the particular traffic flowcomprises the label. Furthermore, the classifying node 101 is configuredto transmit the particular traffic flow comprising the label to the SDN,switch 110 in the SDN 105. The SDN switch 110 is configured to pass thetraffic flow through the SDN 105 based on the label.

In some embodiments, the classifying node 101 comprises means adapted toreceive from a policy node 103, information indicating a filter-settingdefining that a particular traffic flow should be associated with alabel. The means may be further adapted to classify received trafficflows based on the filter-setting such that the particular traffic flowis identified. The means may be adapted to associate based on theclassification, the particular traffic flow with the label such that theparticular traffic flow comprises the label. Furthermore, the means maybe adapted to transmit the particular traffic flow comprising the labelto the SDN, switch 110 in the SDN 105. The SDN switch 110 is configuredto pass the traffic flow through the SDN 105 based on the label.

To perform the method steps shown in FIG. 7 for receiving and handlingtraffic flows in the communications system 100 the classifying node 101may comprise an arrangement as shown in FIG. 8. The classifying node 101may be a gateway node.

The classifying node 101 may comprise a receiving unit 801 which isadapted to receive from the policy node 103, information indicating afilter-setting defining that a particular traffic flow should beassociated with a label. The label may further indicate a direction ofthe traffic flow. The direction may be uplink from a wireless device 125to a base station or downlink from the base station to the wirelessdevice 125. At least one destination 115, 120 for the particular trafficflow may be an intermediate destination 115 configured to provide aservice to be applied to the particular traffic flow. The intermediatedestination 115 may provide a service in a service chain. Thefilter-setting may further indicate which services to be used at adestination 115, 120 for the particular traffic flow. The filter-settingfor the traffic in one direction may be derivable from a label inanother direction. The label may be a part of a data packet header ofdata packets in the particular traffic flow. The label may be one of atleast a part of a flow label in an IPv6 header of data packets in theparticular traffic flow and at least a part of a label in an extensionheader in data packets of the particular traffic flow. The particulartraffic flow may be received from a wireless device 125. The policy node103 may be a PCRF node. The receiving unit 801 may also be referred toas a receiving module, a receiving means, a receiving circuit, means forreceiving or an input unit. The receiving unit 801 may be a receiver, atransceiver etc. The receiving unit 801 may be a wireless receiver ofthe classifying node 101 of a wireless or fixed communications system.

The classifying node 101 may comprise a classifying unit 803 which isadapted to classify received traffic flows based on the filter-settingsuch that the particular traffic flow is identified.

The classifying unit 803 may also be referred to as a classifyingmodule, a classifying means, a classifying circuit or means forclassifying.

The classifying node 101 may comprise an associating unit 805 which isadapted to associate based on the classification, the particular trafficflow with the label such that the particular traffic flow comprises thelabel. The associating unit 805 may also be referred to as anassociating module, an associating means, an associating circuit ormeans for associating.

The classifying node 101 may comprise a transmitting unit 808 adapted totransmit the particular traffic flow comprising the label to the SDNswitch 110 in the SDN 105. The SDN switch 110 is configured to pass thetraffic flow through the SDN 105 based on the label. The transmittingunit 808 may also be referred to as a transmitting module, atransmitting means, a transmitting circuit, means for transmitting or anoutput unit. The transmitting unit 808 may be a transmitter, atransceiver etc. The transmitting unit 808 may be a wireless transmitterof the classifying node 101 of a wireless or fixed communicationssystem.

In some embodiments, the classifying node 101 comprises a processor 810and a memory 813. The memory 813 comprises instructions executable bythe processor 810.

The memory 813 may comprise one or more memory units. The memory 813 isarranged to be used to store data, received data, power levelmeasurements, label-settings, filter-settings, labels, classifications,information, threshold values, time periods, configurations,schedulings, and applications to perform the methods herein when beingexecuted in the classifying node 101.

Those skilled in the art will also appreciate that the receiving unit801, the classifying node 803, the associating unit 805 and thetransmitting unit 808 described above may refer to a combination ofanalog and digital circuits, and/or one or more processors configuredwith software and/or firmware, e.g. stored in a memory, that whenexecuted by the one or more processors such as the processor 810 performas described above. One or more of these processors, as well as theother digital hardware, may be comprised in a single ASIC, or severalprocessors and various digital hardware may be distributed among severalseparate components, whether individually packaged or assembled into aSoC.

The method described above will now be described seen from theperspective of the SDNC 108. FIG. 9 is a flowchart describing thepresent method in the SDNC 108, for handling traffic flows in thecommunications system 100. The SDNC 108 may be located outside the SDN105 and the SDN switch may be 110 located in the SDN 105. The methodcomprises the following steps to be performed by the SDNC 108, whichsteps may be performed in any suitable order than described below:

Step 901

This step corresponds to step 202 in FIG. 2a . The SDNC 108 receivesinformation indicating a label-setting from a policy node 103. Thelabel-setting identifies a label, a particular traffic flow that willpass through the SDN 105 controlled by the SDNC 108, and one or moredestinations 115, 120 for the particular traffic flow.

The label-setting may further indicate a source for the particulartraffic flow.

At least one destination 115, 120 for the particular traffic flow may bean intermediate destination 115 configured to provide a service to beapplied to the particular traffic flow. The intermediate destination 115may provide a service in a service chain.

The label-setting may further indicate a direction of the traffic flow.The direction may be uplink from the wireless device 125 to the SDN 105or downlink from the SDN 105 to the wireless device 125.

The label-setting may further indicate which services to be used at adestination 115, 120 for the particular traffic flow.

The label may be a part of a data packet header of data packets in theparticular traffic flow.

The label may be one of: at least a part of a flow label in an IPv6header in data packets of the particular traffic flow and at least apart of a label in an extension header in data packets of the particulartraffic flow.

In some embodiments, the SDNC 108 and the classifying node 101 have acommon understanding of the label.

The policy node 103 may be a PCRF node and the classifying node 101 maybe a gateway node.

Step 902

This step corresponds to step 203 in FIG. 2. The SDNC 108 creates, basedon the label-setting identifying the label and one or more destinations115, 120, a path-setting comprising the label and a path for theparticular traffic flow through the SDN 105, e.g. as exemplified intable 1 discussed above.

Step 903

This step corresponds to step 204 in FIG. 2. The SDNC 108 transmitsinformation indicating the path-setting to one or more SDN switches 110in the SDN 105.

In some embodiments, a computer program may comprise instructions which,when executed on at least one processor, cause the at least oneprocessor to carry out the method steps 901-903. A carrier may comprisethe computer program, and the carrier is one of an electronic signal,optical signal, radio signal or computer readable storage medium.

To perform the method steps shown in FIG. 9 for handling traffic flowsin the communications system 100, the SDNC 108 is configured to receiveinformation indicating a label-setting from the policy node 103. Thelabel-setting identifies a label, a particular traffic flow that willpass through the SDN 105 controlled by the SDNC 108, and one or moredestinations 115, 120 for the particular traffic flow. The SDNC 108 isfurther configured to create, based on said one or more destinations115, 120, a path-setting comprising the label and a path for theparticular traffic flow through the SDN 105. The SDNC 108 is configuredto transmit information indicating the path-setting to one or more SDNswitches 110 in the SDN 105.

In some embodiments, the SDNC 108 comprises means adapted to receiveinformation indicating a label-setting from a policy node 103. Thelabel-setting identifies a label, a particular traffic flow that willpass through the SDN 105 controlled by the SDNC 108, and one or moredestinations 115, 120 for the particular traffic flow. The means isfurther adapted to create, based on said one or more destinations 115,120, a path-setting comprising the label and a path for the particulartraffic flow through the SDN 105. The means is further adapted totransmit information indicating the path-setting to one or more SDNswitches 110 in the SDN 105.

To perform the method steps shown in FIG. 9 for handling traffic flowsin the communications system 100 the SDNC 108 may comprise anarrangement as shown in FIG. 10. The SDNC 108 may be located outside theSDN 105 and the SDN switch 110 is located in the SDN 105.

The SNDC 108 may comprise a receiving unit 1001 which is adapted toreceive information indicating a label-setting from a policy node 103.The label-setting identifies a label, a particular traffic flow thatwill pass through SDN 105 controlled by the SDNC 108, and one or moredestinations 115, 120 for the particular traffic flow. The label-settingmay further indicate a source for the particular traffic flow. At leastone destination 115, 120 for the particular traffic flow may be anintermediate destination 115 configured to provide a service to beapplied to the particular traffic flow. The intermediate destination 115may provide a service in a service chain. The label-setting may furtherindicates which services to be used at a destination 115, 120 for theparticular traffic flow. The label may be a part of a data packet headerof data packets in the particular traffic flow. The label may be one of:at least a part of a flow label in an IPv6 header in data packets of theparticular traffic flow and at least a part of a label in an extensionheader in data packets of the particular traffic flow. The policy node103 may be a PCRF node, and the classifying node 101 may be a gatewaynode. The receiving unit 1001 may also be referred to as a receivingmodule, a receiving means, a receiving circuit, means for receiving oran input unit. The receiving unit 1001 may be a receiver, a transceiveretc. The receiving unit 1001 may be a wireless receiver of the SDNC 108of a wireless or fixed communications system.

The SNDC 108 may comprise a creating unit 1003 which is adapted tocreate, based on said one or more destinations 115, 120, a path-settingcomprising the label and a path for the particular traffic flow throughthe SDN 105. The filter-setting for the traffic in one direction may bederivable from a label in another direction. The SDNC 108 and theclassifying node 101 may have a common understanding of the label. Thecreating unit 1003 may also be referred to as a creating module, acreating means, a creating circuit or means for creating.

The SNDC 108 may comprise a transmitting unit 1005 which is adapted totransmit information indicating the path-setting to one or more SDNswitches 110 in the SDN 105. The transmitting unit 1005 may also bereferred to as a transmitting module, a transmitting means, atransmitting circuit, means for transmitting or an output unit. Thetransmitting unit 1005 may be a transmitter, a transceiver etc. Thetransmitting unit 1008 may be a wireless transmitter of the SDNC 108 ofa wireless or fixed communications system.

In some embodiments, the SDNC 108 comprises a processor 1008 and amemory 1010. The memory 1010 comprises instructions executable by theprocessor 1008.

The memory 1010 may comprise one or more memory units. The memory 1010is arranged to be used to store data, received data, power levelmeasurements, label-settings, filter-settings, labels, classifications,information, threshold values, time periods, configurations,schedulings, and applications to perform the methods herein when beingexecuted in the SDNC 108.

Those skilled in the art will also appreciate that the receiving unit1001, the creating unit 1003 and the transmitting unit 1005 describedabove may refer to a combination of analog and digital circuits, and/orone or more processors configured with software and/or firmware, e.g.stored in a memory, that when executed by the one or more processorssuch as the processor 1008 perform as described above. One or more ofthese processors, as well as the other digital hardware, may becomprised in a single ASIC, or several processors and various digitalhardware may be distributed among several separate components, whetherindividually packaged or assembled into a SoC.

The present mechanism for handling traffic flows in a communicationsystem 100 may be implemented through one or more processors, such as aprocessor 608 in the policy node 103, a processor 810 in the classifyingnode 101 and a processor 1008 in the SDNC 108, together with computerprogram code for performing the functions of the embodiments herein. Theprocessor may be for example a Digital Signal Processor (DSP), ASICprocessor, Field-programmable gate array (FPGA) processor ormicroprocessor. The program code mentioned above may also be provided asa computer program product, for instance in the form of a data carriercarrying computer program code for performing the embodiments hereinwhen being loaded into at least one of the policy node 103, theclassifying node 101 and the SDNC 108. One such carrier may be in theform of a CD ROM disc. It is however feasible with other data carrierssuch as a memory stick. The computer program code may furthermore beprovided as pure program code on a server and downloaded to at least oneof the policy node 103, the classifying node 101 and the SDNC 108.

Via the policy node 103, it is possible according to the embodimentsherein to coordinate the labelling of the traffic flows before they aretreated by the SDNC 108, i.e. on IP level. The communications system 100may therefore be seen as comprising an associative connection betweenthe classifying node 101 and the SDNC 108.

In planned service chaining solutions, there are ideas to use tagging oftraffic on lower layers, i.e. L2 (most commonly Ethernet) to identify aservice chain. When selecting a path through several services for aspecific traffic flow, the total number of rules that need to bemaintained throughout the path may be a problem. The embodiments hereinmay drastically decrease the number of rules that need to be maintainedand has a potential to hugely simplify the solution.

Furthermore, the embodiments herein may be associated with Layer 3 (L3),i.e. the IP, which makes them transparent to the underlying networktopology. The idea here is to use the flow-label in the IPv6 header andsteer traffic through a set of services based on that. The flow labelmay on the ingress of a chain of services be set to indicate the path totraverse and then all sessions matching that flow-label may be steeredon that alone, instead of creating rules per matching flow or group offlows.

A benefit of using the flow label in IPv6 is that it passestransparently through most destinations 115, 120 unless the destinations115, 120 are instructed and/or configured to modify the label.

Summarized, the classifying node 101 will classify the traffic flowsaccording to the desired policies (what destinations 115, 120 totraverse) and mark the traffic flow with a label. The SDN switches 110may choose to look at this label to steer the traffic flow to thedestination 115, 120. When the traffic flow comes back from thedestination 115, 120 the label will still be intact in the traffic flow,the SDN switches 110 may on the label alone select where to send thetraffic flow next.

The embodiments herein are not limited to the above describedembodiments. Various alternatives, modifications and equivalents may beused. Therefore, the above embodiments should not be taken as limitingthe scope of the embodiments, which is defined by the appending claims.

Some embodiments described herein may be summarized in the followingmanner:

One embodiment is directed to a method in a policy node configured tohandle traffic flows in a communications system. The method comprises:

-   -   allocating a label setting identifying a label, a particular        traffic flow that will pass through a SDN 105, and one or more        destinations 115, 120 for the particular traffic flow;    -   transmitting information indicating the label-setting to a SDNC        108 configured to create a path for the traffic flow through the        SDN 105 based on the label and said one or more destinations        115, 120 identified by the label setting;    -   allocating a filter setting defining that the particular traffic        flow should be associated with the label; and    -   transmitting information indicating the filter setting to a        classifying node 101 configured to receive the particular        traffic flow and to associate the particular traffic flow with        the label.

The label setting may further indicate a source for the particulartraffic flow.

A least one of the destinations 115, 120 may be an intermediatedestination 115 configured to provide a service to be applied to theparticular traffic flow.

The intermediate destination 115 may provide a service in a servicechain.

The filter setting may further indicate a direction of the traffic flow,which direction is uplink from a wireless device 125 to the SDN 105 ordownlink from the SND 105 to the wireless device 125.

The filter setting may further indicate which services to be used at adestination 115, 120 for the particular traffic flow.

The label may be a part of a data packet header of data packets in theparticular traffic flow.

The label may be one of: at least a part of a flow label in an InternetProtocol version 6, IPv6, header in data packets of the particulartraffic flow or at least a part of a label in an extension header indata packets of the particular traffic flow.

The policy node 103 may be a Policy and Charging Rules Function, PCRFnode; and the classifying node 101 may be a gateway node.

Some other embodiments described herein may be summarized in thefollowing manner:

One embodiment is directed to a method in a classifying node 101configured to receive and handle traffic flows in a communicationssystem, the method comprising:

-   -   receiving from a policy node 103, information indicating a        filter setting defining that a particular traffic flow should be        associated with a label;    -   classifying received traffic flows based on the filter setting        such that the particular traffic flow is identified;    -   associating, based on the classification, the particular traffic        flow with the label such that the particular traffic flow        comprises the label; and    -   transmitting the particular traffic flow comprising the label to        a Software Defined Network, SDN, switch 110 in a SDN 105, which        SDN switch 110 is configured to pass the traffic flow through        the SDN 105 based on the label.

The label may further indicate a direction of the traffic flow, whichdirection is uplink from a wireless device 125 to the SDN 105 ordownlink from the SDN 105 to the wireless device 125.

At least one destination 115, 120 for the particular traffic flow may bean intermediate destination 115 configured to provide a service to beapplied to the particular traffic flow.

The intermediate destination 115 may provide a service in a servicechain.

The filter setting may further indicate which services to be used at adestination 115, 120 for the particular traffic flow.

The label may be a part of a data packet header of data packets in theparticular traffic flow.

The label may be one of: at least a part of a flow label in an InternetProtocol version 6, IPv6, header of data packets in the particulartraffic flow or at least a part of a label in an extension header indata packets of the particular traffic flow.

The particular traffic flow may be received from a wireless device(125).

The policy node 103 may be a Policy and Charging Rules Function, PCRFnode, and the classifying node 101 may be a gateway node.

Some other embodiments described herein may be summarized in thefollowing manner:

One embodiment is directed to a method in a Software Defined NetworkController, SDNC 108 configured to handle traffic flow in acommunications system 100, the method comprising:

-   -   receiving information indicating a label setting from a policy        node, which label setting identifies a label, a particular        traffic flow that will pass through a Software Defined Network,        SDN, 105 controlled by the SDNC 108, and one or more        destinations 115, 120 for the particular traffic flow;    -   creating, based on said one or more destinations 115, 120, a        path setting comprising the label and a path for the particular        traffic flow through the SDN 105; and    -   transmitting information indicating the path setting to one or        more SDN switches 110 in the SDN 105.

The label setting may further indicate a source for the particulartraffic flow.

At least one destination 115, 120 for the particular traffic flow may bean intermediate destination 115 configured to provide a service to beapplied to the particular traffic flow.

The intermediate destination 115 may provide a service in a servicechain.

The label setting may further indicate a direction of the traffic flow,which direction is uplink from a wireless device 125 to the SDN 105 ordownlink from the SDN 105 to the wireless device 125.

The label setting may further indicate which services to be used at adestination 115, 120 for the particular traffic flow.

The label may be a part of a data packet header of data packets in theparticular traffic flow.

The label may be one of: at least a part of a flow label in an InternetProtocol version 6, IPv6, header in data packets of the particulartraffic flow or at least a part of a label in an extension header indata packets of the particular traffic flow.

The SDNC 108 and the classifying node 101 may have a commonunderstanding of the label.

The SDNC 108 may be located outside the SDN 105 and the SDN switch(es)110 may be located in the SDN 105.

The policy node 103 may be a Policy and Charging Rules Function, PCRF,node, and the classifying node 101 may be a gateway node.

Some other embodiments described herein may be summarized in thefollowing manner:

One embodiment is directed to a policy node 103 configured to handletraffic flows in a communications system 100. The policy node 103 isconfigured to:

-   -   allocate a label setting identifying a label, a particular        traffic flow that will pass through a Software Defined Network,        SDN, 105, and one or more destinations 115, 120 for the        particular traffic flow;    -   transmit information indicating the label-setting to a SDN        Controller, SDNC 108 configured to create a path for the traffic        flow through the SDN 105 based on the label and said one or more        destinations 115, 120 identified by the label setting;    -   allocate a filter setting defining that the particular traffic        flow should be associated with the label; and to    -   transmit information indicating the filter setting to a        classifying node 101 configured to receive the particular        traffic flow and to associate the particular traffic flow with        the label.

The label setting may further indicate a source for the particulartraffic flow.

At least one of the destinations 115, 120 may be an intermediatedestination 115 configured to provide a service to be applied to theparticular traffic flow.

The intermediate destination 115 may provide a service in a servicechain.

The filter setting may further indicate a direction of the traffic flow,which direction is uplink from a wireless device 125 to the SDN 105 ordownlink from the SDN 105 to the wireless device 125.

The filter setting may further indicate which services to be used at adestination 115, 120 for the particular traffic flow.

The label may be a part of a data packet header of data packets in theparticular traffic flow.

The label is one of: at least a part of a flow label in an InternetProtocol version 6, IPv6, header in data packets of the particulartraffic flow or at least a part of a label in an extension header indata packets of the particular traffic flow.

The policy node 103 may be a Policy and Charging Rules Function, PCRFnode, and the classifying node 101 may be a gateway node.

Some other embodiments described herein may be summarized in thefollowing manner:

One embodiment is directed to a classifying node 101 configured toreceive and handle traffic flows in a communications system, theclassifying node 101 being further configured to:

-   -   receive from a policy node 103, information indicating a filter        setting defining that a particular traffic flow should be        associated with a label;    -   classify received traffic flows based on the filter setting such        that the particular traffic flow is identified;    -   associate based on the classification, the particular traffic        flow with the label such that the particular traffic flow        comprises the label; and to    -   transmit the particular traffic flow comprising the label to a        Software Defined Network, SDN, switch 110 in a SDN 105, which        SDN switch 110 is configured to pass the traffic flow through        the SDN 105 based on the label.

The label may further indicate a direction of the traffic flow, whichdirection is uplink from a wireless device 125 to the SDN 105 ordownlink from the SDN 105 to the wireless device 125.

At least one destination 115, 120 for the particular traffic flow may bean intermediate destination 115 configured to provide a service to beapplied to the particular traffic flow.

The intermediate destination 115 may provide a service in a servicechain.

The filter setting may further indicate which services to be used at adestination 115, 120 for the particular traffic flow.

The label may be a part of a data packet header of data packets in theparticular traffic flow.

The label may be one of: at least a part of a flow label in an InternetProtocol version 6, IPv6, header of data packets in the particulartraffic flow or at least a part of a label in an extension header indata packets of the particular traffic flow.

The particular traffic flow may be received from a wireless device 125.

The policy node 103 may be a Policy and Charging Rules Function, PCRFnode, the classifying node 101 may be a gateway node.

Some other embodiments described herein may be summarized in thefollowing manner:

One embodiment is directed to a Software Defined Network Controller,SDNC 108 configured to handle traffic flow in a communications system100, the SDNC 108 being further configured to:

-   -   receive information indicating a label setting from a policy        node 103, which label setting identifies a label, a particular        traffic flow that will pass through a Software Defined Network,        SDN, 105 controlled by the SDNC 108, and one or more        destinations 115, 120 for the particular traffic flow;    -   create, based on said one or more destinations 115, 120, a path        setting comprising the label and a path for the particular        traffic flow through the SDN (105); and to    -   transmit information indicating the path setting to one or more        SDN switches 110 in the SDN 105.

The label setting may further indicate a source for the particulartraffic flow.

At least one destination 115, 120 for the particular traffic flow may bean intermediate destination 115 configured to provide a service to beapplied to the particular traffic flow.

The intermediate destination 115 may provide a service in a servicechain.

The label setting may further indicate a direction of the traffic flow,which direction is uplink from a wireless device 125 to the SDN 105 ordownlink from the SDN 105 to the wireless device 125.

The label setting may further indicate which services to be used at adestination 115, 120 for the particular traffic flow.

The label may be a part of a data packet header of data packets in theparticular traffic flow.

The label may be one of: at least a part of a flow label in an InternetProtocol version 6, IPv6, header in data packets of the particulartraffic flow or at least a part of a label in an extension header indata packets of the particular traffic flow.

The SDNC 108 and the classifying node 101 may have a commonunderstanding of the label.

The SDNC 108 may be located outside the SDN 105 and the SDN switch 110may be located in the SDN 105.

The policy node 103 may be a Policy and Charging Rules Function, PCRF,node, and the classifying node 101 may be a gateway node.

Some other embodiments described herein may be summarized in thefollowing manner:

One embodiment is directed to a computer program comprising instructionswhich, when executed on at least one processor, cause the at least oneprocessor to carry out the method according to any one of theembodiments described herein.

One embodiment is directed to a carrier comprising the computer program,wherein the carrier is one of an electronic signal, optical signal,radio signal or computer readable storage medium.

It should be emphasized that the term “comprises/comprising” when usedin this specification is taken to specify the presence of statedfeatures, integers, steps or components, but does not preclude thepresence or addition of one or more other features, integers, steps,components or groups thereof. It should also be noted that the words “a”or “an” preceding an element do not exclude the presence of a pluralityof such elements.

The term “configured to” used herein may also be referred to as“arranged to”, “adapted to”, “capable of” or “operative to”.

It should also be emphasised that the steps of the methods defined inthe appended claims may, without departing from the embodiments herein,be performed in another order than the order in which they appear in theclaims.

The invention claimed is:
 1. A method in a policy node configured tohandle traffic flows in a communications system, the method comprising:in a policy node separate from a Software Defined Network, SDN,controller: allocating a label-setting identifying a label, a particulartraffic flow that will pass through a Software Defined Network, SDN, andone or more destinations for the particular traffic flow, the labelidentifying at least one of: traffic from a defined source and havingany destination; traffic having a defined destination and from anysource; traffic from a defined application; and traffic requiring adefined set of one or more services and having any source ordestination, wherein one label can be assigned to multiple flows andwherein multiple labels can be assigned to one flow, and wherein onelabel can be associated with multiple services and wherein multiplelabels can be associated with one service; transmitting informationindicating the label-setting to the SDN Controller, SDNC, configured tocreate a path for the traffic flow through the SDN based on the labeland said one or more destinations identified by the label-setting;allocating a filter-setting defining that the particular traffic flowshould be associated with the label; and transmitting informationindicating the filter-setting to a classifying node configured toreceive the particular traffic flow and to associate the particulartraffic flow with the label.
 2. The method according to claim 1, whereinthe label-setting further indicates a source for the particular trafficflow.
 3. The method according to claim 1, wherein at least one of thedestinations is an intermediate destination configured to provide aservice to be applied to the particular traffic flow.
 4. The methodaccording to claim 1, wherein the filter-setting further indicates whichservices to be used at a destination for the particular traffic flow. 5.The method according to claim 1, wherein the label is one of: at least apart of a flow label ln an Internet Protocol version 6, IPv6, header indata packets of the particular traffic flow and at least a part of alabel in an extension header in data packets of the particular trafficflow.
 6. A method in a classifying node configured to receive and handletraffic flows in a communications system, the method comprising:receiving from a policy node, information indicating a filter-settingdefining that a particular traffic flow should be associated with one ormore labels, each of the one or more labels identifying at least one of:traffic from a defined source and having any destination; traffic havinga defined destination and from any source; traffic from a definedapplication; and traffic requiring a defined set of one or more servicesand having any source or destination, wherein one label can be assignedto multiple flows and wherein multiple labels can be assigned to oneflow, and wherein one label can be associated with multiple services andwherein multiple labels can be associated with one service; classifyingreceived traffic flows based on the filter-setting such that theparticular traffic flow is identified; associating based on theclassification, the particular traffic flow with the label such that theparticular traffic flow comprises the label; and transmitting theparticular traffic flow comprising the label to a Software DefinedNetwork, SDN, switch in a SDN, which SDN switch is configured to passthe traffic flow through the SDN based on the label.
 7. A method in aSoftware Defined Network Controller, SDNC configured to handle trafficflow in a communications system, the method comprising: receivinginformation indicating a label-setting from a policy node, whichlabel-setting identifies a label, a particular traffic flow that willpass through a Software Defined Network, SDN, controlled by the SDNC,and one or more destinations for the particular traffic flow, the labelidentifying at least one of: traffic from a defined source and havingany destination; traffic having a defined destination and from anysource; traffic from a defined application; and traffic requiring adefined set of one or more services and having any source ordestination, wherein one label can be assigned to multiple flows andwherein multiple labels can be assigned to one flow, and wherein onelabel can be associated with multiple services and wherein multiplelabels can be associated with one service; creating, based on said oneor more destinations, a path-setting comprising the label and a path forthe particular traffic flow through the SDN; and transmittinginformation indicating the path-setting to one or more SDN switches inthe SDN.
 8. The method according to claim 7, wherein the label-settingfurther indicates a source for the particular traffic flow.
 9. Themethod according to claim 7, wherein at least one destination for theparticular traffic flow is an intermediate destination configured toprovide a service to be applied to the particular traffic flow.
 10. Themethod according to claim 7, wherein the label-setting further indicateswhich services to be used at a destination for the particular trafficflow.
 11. The method according to claim 7, wherein the label is one of:at least a part of a flow label in an Internet Protocol version 6, IPv6,header in data packets of the particular traffic flow and at least apart of a label in an extension header in data packets of the particulartraffic flow.
 12. The method according to claim 7, wherein the SDNC andthe classifying node have a common understanding of the label.
 13. Apolicy node configured to handle traffic flows in a communicationssystem, the policy node being separate from a Software Defined Network,SDN, controller and further configured to: allocate a label-settingidentifying a label, a particular traffic flow that will pass through aSoftware Defined Network, SDN, and one or more destinations for theparticular traffic flow, the label identifying at least one of: trafficfrom a defined source and having any destination; traffic having adefined destination and from any source; traffic from a definedapplication; and traffic requiring a defined set of one or more servicesand having any source or destination, wherein one label can be assignedto multiple flows and wherein multiple labels can be assigned to oneflow, and wherein one label can be associated with multiple services andwherein multiple labels can be associated with one service; transmitinformation indicating the label-setting to a SDN Controller, SDNCconfigured to create a path for the traffic flow through the SDN basedon the label and said one or more destinations identified by thelabel-setting; allocate a filter-setting defining that the particulartraffic flow should be associated with the label; and to transmitinformation indicating the filter-setting to a classifying nodeconfigured to receive the particular traffic flow and to associate theparticular traffic flow with the label.
 14. A Software Defined NetworkController, SDNC configured to handle traffic flow in a communicationssystem, the SDNC being further configured to: receive informationindicating a label-setting from a policy node, which label-settingidentifies a label, a particular traffic flow that will pass through aSoftware Defined Network, SDN, controlled by the SDNC, and one or moredestinations for the particular traffic flow, the label identifying atleast one of: traffic from a defined source and having any destination;traffic having a defined destination and from any source; traffic from adefined application; and traffic requiring a defined set of one or moreservices and having any source or destination, wherein one label can beassigned to multiple flows and wherein multiple labels can be assignedto one flow, and wherein one label can be associated with multipleservices and wherein multiple labels can be associated with one service;create, based on said one or more destinations, a path-settingcomprising the label and a path for the particular traffic flow throughthe SDN; and to transmit information indicating the path-setting to oneor more SDN switches in the SDN.